Print

[shane g]

Hi guys
i am new to the site i have read alot before i joined and i finaly made the decision to build my own owb
if any of you guys could help it would be appreciated
heres the deal i have a 1200 square foot home i want to build a owb that will heat my home and a 30x30 garage i plan to build eventualy i work at a factory that i get sheet steel at a deal
i have already aquired   6 sheets of 5'x5' 1/4' that i was going to use for a water jacket
i am wondering what type of firebox i should build i was looking at building a (ripple top)type like i think cb uses or a round like a shaver i am looking at what would be the most eficient and what would produce the least amount of smoke so my questions are
what firebox is the best?
how should i position the flu in the firebox?
should i use a blower or a natural draft?
any suggestions will be a big help i basicaly know how they work but dont have any specifics
i will be the first one around here to build a stove and i want it to be as eficient as possible
i would like to build a stove like jackell440 but thats a little complex for my first stove
thanks in advance for any help

[jackel440]

Welcome to site!
Lots of great guys here to help.I am more than glad to help you if I can.
Unless you have access to a press brake to form the ripple bends in the top I would for gore that plan.Too many seams to weld for each ripple.
Now I would build a fire box with flat sides and octagon shaped to some point. heat transfer happens faster on a flat surface than a round surface.
I would then go and study different design stove exhaust passage designs.I am a big fan of how the Portage and Mains are designed.
they have access to clean the exhaust and are double pass to extract heat in the water jacket.
I would definetly go with an blower.I like to the fire to pick up fast and start producing heat,rather than lazily stoking back up.
I would use your 1/4" for your fire box.Then get some 1/8" or 3/16" for your water jacket.I used 10 guage.Heck water tanks and oil tanks aren't that thick.
You could build a stove like mine.You would actually be way ahead if you did build a gassifier.They use less wood and smoke alot less.
Don't put that option out yet,You will find that after you build this once you wont be in a big hurry to do it again.
Make lots of drawings and try to keep track of the big picture of how everything works together.Always be planning 5 steps ahead.
take your time ,and think out every step of your build.
good luck,and oh yeah take lots of pics!    

[shane g]

Jackel440,
thanks for the warm welcome. I actually have acces to a huge press brake  a nice deltaweld miller mig
plasma metal cutting laser ect. i am a  maintenance mechanic for a truck manufactoring plant here in VA. and i have gotten permision from my boss to build it in the shop on my off time (what little i get ) if you think a octogon style box is better i may go that route it still would be less welding i cant find a design on the web about the port and main  flu design they did say on their site smoke goes below through a slot in the firebox I still can't comprehend smoke going below the fire seems to me like it would choke out but then again i am still in the learning stages of the designs
let me air out my thoughts on a flu design a 3x3 firebox ripple or octogon flu positioned 2/3 of the way down in the back of the box coming out the top then 90 then out through the the back of the water jacket with a tee on the out side of the stove  for clean out and if i build the octogon shape put a deflector in front of the flu in the firebox to trap the smoke  also the blower comes in from the back and blows underthe grate to excite the fire from underneath instead of a blower on the door
this is just my thoughts i am open to ideas
also should the flu itself have any kind of baffle or dampner in it
any way i am holding anymore questions on the other things dont want to overload anybodys brain
i have a ton of questions
jackel440 thanks for help i envy your stove that thing is killer iwill be calling on you often sounds like you have done some trial and error

[Bull]

Welcome to the site shane, there are plenty of guys here with some great ideas. Remember take plenty of pictures and keep us informed of your build.
Bill

[newmod]

Shane,
     Good luck with your build.  I am in the process of building mine now.  I was planning on following the Central Boiler style with ripple also, But found it much easier to put the heat transfer tubes through the top of the firebox.  Actually we don't have a whole lot of man hours involved in building it so far.  The outside dimensions of mine are 48 x 48 x 48.  firebox is 30 x 30 x 42.  Will hold almost 300 gallons of water.

Newmod

[mikenc]

Welcome Shane, I think Portage & Mane Flue goes from back out of fire box to front then back to back and out top of stove. Any way here is a link showing flue.
Good luck on your build!!!!





http://www.portageandmainboilers.com/pdf_brochures/ShakergrateWebColor%20apr7.pdf

[rosewood]

anything you build you will be happy with.  if you build the  traditional style furnace , i would recommend octogon or round,mainly for the strength,square has creasote issues worst.i have a round style and it has very little acumulation of creasote.the flu down low in the firebox is good ,smoke has to pass by hot coals helping it gasify . if you decide to build a gassifier style ,you need to ask yourself if the extra labor and materials  are going to pay off? it might be the diiference of a cord or two in savings,if you buy cord wood in log lenght thats about 150 bucks more ..around here anyway ,not really much. gassers are supposed to be less smoke but once you get the hang of it you can get the old style to do very well. last , i never hear guys say anything about using stainless steel for the water jacket? this is undoubtably the biggest problem with owb ,how many posts and pics have you seen on here with rott holes in water tank. the cost of 304 grade i know is alot but look how much your saving...i think its a good investment. ......just my 2 cents.

[shane g]

wow first i want to thank everybody on here i never dreamed there would be a forumthat would be as helping as this one i have learned more to day then i have in a month there is not alot of stoves around here the ones that are here are mostly  taylors people bought like 10 years ago so from what i have seen i am going to be the first to build my own
the octogon shape is starting to grow on me and if putting the flu pipe down in the fire box would help and then out the top of the firebox then 90 out the back of the water jacket
wood here is not that big of an issue i am on a 500 acre hunting lease  and i can cut as much dead and down wood i want and if i run out there i can pay 13.50 for a forrestry permit and cut up to 10 cords a year i just want a eficient stove that is not going to tick off everybody around me with the smoke

[rosewood]

by the way welcome! there are some really good people with good info here,if you take bits and pieces and combine them youll do something cool. sounds like you got the basics figured out. 2 things that help with the effiecentcy ,getting the gasses to ignite prior to leaving firebox,and capturing the heat in the exhaust. if you go to garn wood furnaces and check out the ''little magic refractory piece ''they use in the exhaust . that is where it gets super heated to ignite unburned fuel..smoke. then it runs thru a good length of exhaust ,submerged in water before it exits out.if you can do these things youll be sure to get the results your looking for.

[shane g]

okay guys been studying on gasification i think with all the input on here i am going to build the octogon firebox 34"wide x 34" high x 42" long here is my understanding of how it works on the the down draft gassifier
i build a box attached to the bottom of the firebox with slots in the bottom of firebox going in to the gasifier box  thinking the gasifier would be 10"x10"
the slots in the fire box being1"wide x 4" long and put 4 of them in spaced roughly 4-6" apart come out the back of the gasifier with my flu and 90 up through the top of  waterjacket that would give me 53" of flu pipe inside the water jacket
please everybody give me your honest opinion
thanks

[rosewood]

i would think that the chamber needs some type of refractary brick and extra oxygen to get it to gassafy. by your measurements those slots equall 16 sq '' not sure if its to small? youll need a fan that puts out a lot of cfm.

[jackel440]

Your only going to need to decide on a nozzle size.Meaning your hole through the floor and into a refractory chamber.You willl have to have refractory block in the secondary burn chamber due to the high heat and burn temps.You will need a passage to feed frsh air to the nozzle to feed the gas chamber burn.
You will also need to feed air to the burn chamber so as to pressurize it and to force the smoke down through your nozzle.
Now I have considered going to a single nozzle on my stove just to see if there is any performance difference.I currently have 2 slots in my floor.
My stove runs a 500cfm blower to feed air to both chambers.
Now you need to have the brick to hold the heat to help restart the gasification burn at each cycle.Plus protcet the steel from the high heat.Now you need to design a long enough passage to extract all the heat from the secondary burn to be used to reheat the water in the water jacket.
I have the 6 3" pipes flowing from the double passage refractory chamber up through my water tank.
Now you will also need to design a bypass in your fire box to allow the smoke to exit out the top of your firebox when you first start your stove or are loading it.If not you will have smoke rolling out the door at you ,and you wont be able to see anything.
Plus I have had flash backs from the wood gas igniting as soon as it comes out the door and fresh air mixes with flame from the fire box igniting it.Only for a second does it happen and not always.This only happens if the bypass is shut and I try to load it while it is running.even though I have flipped the load switch on to kill the fan.
Some more tidbits for you to think about.

[shane g]

Wow i was way off i guess i need to do some more research although the more i look at jackel's pics on here the more i understand so going to keep studying lol
just got to get my mind wrapped around it thanks for the help guy's

[rosewood]

jackel, if you made some blueprints from your furnace you probably would be a millionaire about now! lol..online price $19.99 and he''ll throw in the knives!

[shane g]

yeah and pay for overnight shipping so i could start tomorrow